Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations

Handle URI:
http://hdl.handle.net/10754/623786
Title:
Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations
Authors:
Mai, Paul Martin ( 0000-0002-9744-4964 ) ; Galis, Martin ( 0000-0002-5375-7061 ) ; Thingbaijam, Kiran Kumar ( 0000-0002-2415-2266 ) ; Vyas, Jagdish Chandra; Dunham, Eric M.
Abstract:
Geological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω−2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Mai PM, Galis M, Thingbaijam KKS, Vyas JC, Dunham EM (2017) Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations. Pure and Applied Geophysics. Available: http://dx.doi.org/10.1007/s00024-017-1536-8.
Publisher:
Springer Nature
Journal:
Pure and Applied Geophysics
KAUST Grant Number:
BAS/1339-01-01; URF/1/2160-01-01
Issue Date:
3-Apr-2017
DOI:
10.1007/s00024-017-1536-8
Type:
Article
ISSN:
0033-4553; 1420-9136
Sponsors:
We are grateful to L. Dalguer, Ph. Renault, and Y. Fukushima who organized the initial international IAEA-workshop on Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (Best-PSHANI), Nov 18-21, 2015, Vienna. The presentations and discussions during this conference inspired us to expand our rough-fault dynamic rupture simulations. Comments and constructive criticism by Guest Editor L. Dalguer and two reviewers greatly helped to focus and clarify this study. Research presented in this paper is supported by King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia, Grants BAS/1339-01-01 and URF/1/2160-01-01. Earthquake rupture and ground-motion simulations have been carried out using the KAUST Supercomputing Laboratory (KSL), and we acknowledge the support of the KSL staff.
Additional Links:
http://link.springer.com/article/10.1007%2Fs00024-017-1536-8
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorMai, Paul Martinen
dc.contributor.authorGalis, Martinen
dc.contributor.authorThingbaijam, Kiran Kumaren
dc.contributor.authorVyas, Jagdish Chandraen
dc.contributor.authorDunham, Eric M.en
dc.date.accessioned2017-05-31T11:23:05Z-
dc.date.available2017-05-31T11:23:05Z-
dc.date.issued2017-04-03en
dc.identifier.citationMai PM, Galis M, Thingbaijam KKS, Vyas JC, Dunham EM (2017) Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations. Pure and Applied Geophysics. Available: http://dx.doi.org/10.1007/s00024-017-1536-8.en
dc.identifier.issn0033-4553en
dc.identifier.issn1420-9136en
dc.identifier.doi10.1007/s00024-017-1536-8en
dc.identifier.urihttp://hdl.handle.net/10754/623786-
dc.description.abstractGeological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω−2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.en
dc.description.sponsorshipWe are grateful to L. Dalguer, Ph. Renault, and Y. Fukushima who organized the initial international IAEA-workshop on Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (Best-PSHANI), Nov 18-21, 2015, Vienna. The presentations and discussions during this conference inspired us to expand our rough-fault dynamic rupture simulations. Comments and constructive criticism by Guest Editor L. Dalguer and two reviewers greatly helped to focus and clarify this study. Research presented in this paper is supported by King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia, Grants BAS/1339-01-01 and URF/1/2160-01-01. Earthquake rupture and ground-motion simulations have been carried out using the KAUST Supercomputing Laboratory (KSL), and we acknowledge the support of the KSL staff.en
dc.publisherSpringer Natureen
dc.relation.urlhttp://link.springer.com/article/10.1007%2Fs00024-017-1536-8en
dc.subjectEarthquake rupture dynamicsen
dc.subjectfault-surface roughnessen
dc.subjectphysics-based ground-motion simulationsen
dc.subjectnear-fault shakingen
dc.subjectseismic hazarden
dc.titleAccounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulationsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalPure and Applied Geophysicsen
dc.contributor.institutionDepartment of Geophysics, Stanford University, Stanford, USAen
kaust.authorMai, Paul Martinen
kaust.authorGalis, Martinen
kaust.authorThingbaijam, Kiran Kumaren
kaust.authorVyas, Jagdish Chandraen
kaust.grant.numberBAS/1339-01-01en
kaust.grant.numberURF/1/2160-01-01en
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